Buoyant water purification pad

The present invention relates to a purification apparatus for removing contaminants from surfaces of water bodies, and more particularly to a buoyant floatation pad which is provided with a sorptive laminar core configured to absorb and/or adsorb contaminants such as hydrocarbons, fats and/or esters which are dispersed on the water surface.

In the remediation of marine oil spills, it is known to deploy containment booms as a floating barrier to contain spilt oil and prevent the dispersion of hydrocarbons more broadly over the water surface. Typically, the containment boom is floated on the water body surface and forms a physical barrier against oil movement, allowing for its concentration and mechanical collection by oil skimmers, vacuum pumps and the like.

The use of conventional boom and mechanical collection techniques in spill remediation however, presents challenges in dealing with spills of both thinner light hydrocarbons, as well as those which extend over more open areas and/or on larger water body surfaces where wind and wave action may result in contaminants washing over and past the boom.

Consideration has been given to using buoyant, oil absorptive non-woven fiber mats as a means to absorb and preferentially trap the spilt hydrocarbons, so as to limit their further dispersal. The applicant has appreciated however, that in addition to difficulties with respect to the size of absorbent mats required and physical challenges in their deployment, once saturated, the added weight of the absorbed oil would make such mats extremely unwieldy, hindering both their removal after use, as well as the possible recycling of any oil products absorbed thereby.

It is an object of the present invention to provide a buoyant water purification or containment mat or pad which allows for the capture and/or removal of contaminants such as oils, fats and esters which are dispersed on a water body surface.

In one non-limiting embodiment, a buoyant mat or pad is provided which is configured to be floated on a water body surface to preferentially absorb and/or adsorb contaminants, and preferably hydrocarbons such as oils, diesel fuels, gasoline and the like, from a water body surface, allowing for the contaminant, capture and collection thereby. More preferably, the buoyant pad is provided with a generally flattened lateral shape which is adapted for positioning on the water body surface to assist in purifying the water body by the preferential sorption of contaminants into the pad interior. More preferably, the pad allows for release and recycling of collected contaminants, by physically pressing or rolling the pad following contaminant saturation.

In one envisioned use, the contaminant sorptive pad may be deployed alone or as part of a tethered array by floating on a water body surface, such as the ocean or a lake environment, as a means of mitigating or remediating chemical, oil or other fuel spills. In other applications, contaminant sorptive pads may be deployed on the surface of a swimming pool or hot tub to facilitate the collection and removal of contaminants such as oils, fatty acids and/or esters, such as those which emanate from user sunscreens and/or skin care products.

In another non-limiting embodiment, a number of buoyant floatation pads may be provided as modular components which are adapted to be tethered or fixedly secured relative to each other and floated on a water body surface to function as a physical containment boom which, in addition to providing for the absorption and/or adsorption of contaminant oils and/or other hydrocarbons, functions as a physical barrier to limit contaminant dispersion.

The sorptive pad preferably is adapted to assist in contaminant removal and water body purification. The pad includes one or more laminar cores which are formed from a number of stacked or laminar fabric or fabric-like layers. The laminar layers are selected and configured to preferentially absorb, and preferably also adsorb hydrocarbons, fats, esters and/or other contaminants. The laminar core layers are more preferably formed from a superabsorbent microfiber material such as polypropylene. Although not essential, the microfiber material is most preferably a non-woven fabric which is at least partially hydrophobic, and which has a density less than seawater or freshwater, depending on the intended pad usage.

Whilst not essential, in one embodiment, the laminar core is formed with a plurality of meltblown polypropylene sheet layers which are provided in a side-by-side lateral or horizontally stacked juxtaposed arrangement. More preferably the core layers are provided with a side-by-side stacked juxtaposed arrangement so that when the pad is deployed, the inter-layer spacing between adjacent layers is generally vertically elongated in a direction normal to the water surface, and with the spacing selected to facilitate wicking and capillary movement of hydrocarbons and other contaminants from a surface portion of the water body, towards and into the pad interior.

In one possible construction, the laminar core is formed as a stacked construct of generally aligned and parallel oriented fabric sheets. In another possible construction, the core is provided with one or more spiral-wound coil bodies formed by winding or coiling one or more elongated fabric or meltblown polypropylene sheets spirally about a central axis. The meltblown polypropylene sheets most preferably have a porosity structure selected to be at least partially hydrophobic, whilst allowing for the preferential absorption and adsorption of hydrocarbons or other contaminants within the core, to facilitate their collection and removal thereby.

In another embodiment, a contaminant sorptive body is provided as part of a 3″ to 72″ diameter pad and more preferably a disk-shaped pad. The pad preferably extends with a vertical thickness selected at between about 0.5 to 12″, and preferably about 0.5 to 3″, with parallel upper and lower surfaces. The sorptive buoyant body may incorporate one or more laminar cores. Optionally, the laminar cores may be mounted to or sandwiched between one or more rigid or semi-rigid fluid porous panels.

In another embodiment, the laminar core is formed having a plurality of generally vertically oriented, stacked or juxtaposed fabric layers or sheets. Preferably the juxtaposed sheet layers are formed by coiling a meltblown polypropylene sheet spirally about a central axis. More preferably, the coiled sheet layers are secured or fixed under a winding tension selected to provide the laminar core with a rigidity or semi-rigidity selected to maintain a side-by-side stacked sheet layer arrangement, and resist the lateral deformation or vertical deflection of the laminar core against wave action.

Optionally, porous covering sheet layers may be provided over and/or enveloping the upper and lower surfaces of the sorption body surfaces. In one possible construction, the covering sheets may be provided as fluid permeable spunbond polypropylene sheets. Optionally, the spunbond polypropylene sheets may be glued, or heat fused or welded to an associated coiled, meltblown polypropylene laminar core, to assist in maintaining the stacked or wound core layer orientation.

In another embodiment, the present invention provides an absorptive/adsorptive contaminant containment pad or mat which may be used to assist in the collection and/or possible recycling or reuse of contaminates which have been spilt on the ground or on the building floor surfaces. Preferably, the containment mat is adapted to collect and/or to limit or prevent the further spread of contaminant spills. It is envisioned that on the occurrence of a spill, the containment pad could be physically positioned over the spilt contaminants and contaminated area, and optionally, pressure may be applied thereto, as for example to facilitate absorption and the capillary wicking of contaminants into the laminar core layers.

Where buoyancy of the containment pad is less of a concern, as for example where the pad is to be used in the collection of contaminants on hard surfaces such as the ground or floor, the laminar core may be treated to increase hydrophilic properties of the laminar core layers, and increase the overall absorptive capacity of the pad.

In a further embodiment, the spirally wound laminar core layers may be treated to facilitate contaminant wicking. Suitable compounds for treating the coiled core fabric layers include without restriction the coating or impregnation of meltblown microfiber fabric with surfactants, as well as the use of additives in the form of pellets to be added to the polypropylene resin in the plastic extruder to produce a meltblown non-woven fabric which is hydrophilic so it can better absorb water and other sort of chemicals.

In another non-limiting embodiment, the meltblown polypropylene sheet used to form laminar core layers is impregnated with a suitable wetting agent such as VW451™ sold by Polyvel Inc. or NuWet 550™ sold by Momentive Performance Materials Inc. In other possible configurations, wetting agents may be applied selectively to either the bottom and/or top surfaces of the laminar core and/or its cover layers to facilitate preferential absorption and wicking of fluids into bottom and/or top surfaces of the absorptive body.

In another embodiment, the absorptive pad may be provided as an oil absorptive drum topper for positioning on 55 gallon drums which are stacked or unstacked to collect spills.

In other embodiments, the water purification pad is provided as a buoyant pad for use on swimming pools or hot tubs to assist in the removal of oily substances such as fats or esters originating from cosmetic products, sunscreens and the like.

The present invention may reside in various non-limiting aspects, and which for example may include without restriction:

The apparatus according to any of the preceding or hereafter described aspects, wherein the apparatus is at least partially buoyant and is adopted for the removal of said contaminates from a water body surface, the apparatus further comprising: a first fluid porous cover member positioned over the upper sorption body surface, a second fluid porous cover member being positioned over the lower sorption surfaces, wherein each of the first and second porous cover members, comprise polypropylene.

The apparatus according to any of the preceding or hereafter described aspects, further comprising at least one respective heat weld thermally fusing a portion of each of the first and second cover members respectively to a respective upper and lower surface.

The apparatus according to any of the preceding or hereafter described aspects, wherein said laminar core comprises a non-woven microfiber sheet which is spirally wound radially about a generally vertical axis, and/or wherein said polypropylene sheet layers comprise spirally adjacent polypropylene sheet layers which are secured under a winding tension, and/or whereby said laminar core has a rigidity selected to resist deformation when said apparatus is positioned on said water body surface.

The apparatus according to any of the preceding or hereafter described aspects, wherein said sorption body has a specific gravity of less than about 1.

The apparatus according to any of the preceding or hereafter described aspects, wherein the laminar core comprises a spirally wound non-woven meltblown polypropylene sheet strip, and/or said sheet strip being substantially hydrophobic, and/or wherein said first and second cover members comprise substantially hydrophobic spunbond polypropylene fabric layers.

The apparatus according to any of the preceding or hereafter described aspects, wherein the polypropylene sheet layers are provided in a generally vertically oriented, laterally stacked side-by-side orientation as part of a substantially continuous, spiral wound meltblown polypropylene sheet winding, and/or said polypropylene sheet winding comprising a 20 to 100 gsm meltblown non-woven fabric.

The apparatus according to any of the preceding or hereafter described aspects, wherein said sorption body comprises a generally disk-shaped pad having generally planar parallel spaced upper and lower surfaces and/or a radial diameter selected at between about 3 and 72 inches, preferably between about 6 and 36 inches and more preferably between about 8 and 26 inches, and/or a vertical thickness selected at between about 0.5 and 8 inches, preferably between about 1 and 6 inches and most preferably between about 1.5 and 6 inches.

The apparatus according to any of the preceding or hereafter described aspects, wherein the sorption body includes at least one through-bore extending generally vertically through an axial center of said winding, the sorption body optionally including a reinforcing plug positioned at said axial center and defining said through-bore, and/or wherein the reinforcing plug comprises polypropylene or polyethylene.

An oil containment boom for the collection and/or containment of contaminant oil, wherein said containment boom comprises a plurality of the apparatus according to any of the preceding or hereafter described aspects tethered together in a generally edge-to-edge orientation.

The apparatus according to any of the preceding or hereafter described aspects, wherein said microfiber polypropylene sheet comprises a 10 to 150 gsm, preferably 20 to 100 gsm, and most preferably a 40 to 80 gsm, non-woven fabric having a density less than about 1 gm/cm, and/or said microfiber polypropylene sheet being secured under a coiled tension selected to substantially maintain said laminar core with lateral integrity selected to substantially withstand wind or wave action when said sorption body is floated on said water body.

The apparatus according to any of the preceding or hereafter described aspects, wherein said laminar core is a generally disk-shaped core having a vertical thickness of between about 0.5 and 8 inches, preferably about 1 and 4 inches, and/or radial diameter selected at between about 3 and 72 inches, and more preferably about 12 to 36 inches.

The apparatus according to any of the preceding or hereafter described aspects, further including at least one fixing member, physically securing at least some of said polypropylene sheet layers in a tension coiled position in said substantially side-by-side juxtaposed arrangement.

The apparatus according to any of the preceding or hereafter described aspects, wherein said fixing member comprises a thermal weld physically melt fusing said at least some laterally adjacent ones of said polypropylene sheet layers.

The apparatus according to any of the preceding or hereafter described aspects, comprising a plurality, preferably at least four, and most preferably at least eight of said fixing members, and/or wherein each said fixing member comprising an elongate thermal weld extending radially relative to said vertical axis and physically melt fusing said at least some laterally adjacent said polypropylene sheet layers.

The apparatus according to any of the preceding or hereafter described aspects, wherein said laminar core is interposed between, and preferably substantially enveloped by, a top cover member and a bottom cover member, each of the cover members having a fluid porosity selected to permit the substantially unhindered movement of water and contaminants therethrough.

The apparatus according to any of the preceding or hereafter described aspects, wherein at least one, and preferably both of the cover members comprise spunbond polypropylene fabric sheets of 25 to 60 gsm, and preferably sheets of 30 to 50 gsm.

The apparatus according to any of the preceding or hereafter described aspects, wherein each spunbond polypropylene sheet is at least partially melt fused to at least some of said polypropylene sheet layers by at least one said fixing member.

The apparatus according to any of the preceding or hereafter described aspects, wherein the non-woven polypropylene sheet layers and/or the top cover member and/or bottom cover member, are chemically impregnated sheet layers which are impregnated with a wetting agent to increase hydrophilic properties.

The apparatus according to any of the preceding or hereafter described aspects, wherein the microfiber material strip comprises a 20 to 100 gsm meltblown non-woven polypropylene strip, said strip being wound about said vertical axis and defining a plurality of vertically oriented juxtaposed sheet layers, stacked laterally as a side-by-side array, and/or wherein the polypropylene sheet being secured under a coiled tension selected to assist in maintaining at least partial lateral integrity of said sorption body when positioned on said water body surface.

The apparatus according to any of the preceding or hereafter described aspects, wherein the sorption body includes an axially oriented through-bore, said apparatus further comprising a tether assembly received at least partially in the through-bore to facilitate positioning and/or retrieval of the apparatus from the water body surface,

The apparatus according to any of the preceding or hereafter described aspects, wherein at least one of the top sheet and the bottom sheet comprises a fluid permeable, spunbond polypropylene sheet, and preferably a 25 to 50 gsm hydrophobic polypropylene sheet.

The apparatus according to any of the preceding or hereafter described aspects, comprising a plurality of pairs of said heat welds, said heat weld pairs being opposedly formed in portions of said respective first and second cover sheets, and/or wherein the welds being generally elongated in an orientation extending radially from said vertical axis.

The apparatus according to any of the preceding or hereafter described aspects, wherein each of the first and second polypropylene sheets comprise a 25 to 60 gsm spunbond polypropylene fabric sheet.

A method of manufacturing an apparatus and preferably a water purification apparatus according to any of the preceding or hereafter described aspects, comprising: cutting a sheet of non-woven meltblown polypropylene material to strips, forming a roll body by coiling a selected said strip about a rotatable mandrel, under a winding tension whereby the roll body is formed having generally planar upper and lower surfaces, with said roll body removed from said mandrel joining a first layer and a second layer of polypropylene material by heat welding with the roll body interposed the first layer and the second layer, attaching a connecting member to the purification apparatus wherein the connecting member can be used to connect a further purification apparatus.

The method according to any preceding aspects, wherein said step of heat welding comprises forming a plurality of elongated melt welds radially in said roll body and wherein at least one melt weld partially melt fuses a portion of the first cover layer, and an adjacent portion of the roll body.

Reference may now be had towhich illustrates an oil spill containment boomwhich as will be described, is used in preventing the spread and dispersal of contaminate oilacross the water surface, of the water bodyin accordance with a preferred embodiment of the invention. The containment boomis shown as being comprised of a number of buoyant water purification flotation pads. Each of the padsare of a modular construction and are adapted to be tethered to each other to form the boomwith the desired width, and elongated length. Any number of flotation padsmay be provided to form the containment boomas a physical barrier which prevents or restricts the dispersal of the oilover the water surfacetherepast. Most preferably, the selected number of flotation padsare interconnected so as form the containment boom, with overall width and length of the boomchosen depending on the extent of the spilt contaminate oilto be collected, and the nature of the particular water body.

As will be described, in addition to forming a physical barrier, the individual flotation padsare configured to further selectively absorb and preferably also adsorb the oilfrom the water surfaceof the water body, allowing for collection and removal of the spilt oilfrom the water bodytherewith.

illustrate best the overall configuration of each floatation pad. The flotation padpreferably has a generally flattened disk-shaped construction, with generally planar, parallel upper and lower surfaces,, and a peripheral outer edgewhich extends radially about an axially aligned through bore. To allow for simplified storage, transport and/or retrieval following use, the flotation padpreferably is formed with a lateral radial diameter D of between 6 and 36 inches, preferably about 24 to 36 inches, and extends with a thickness T in the vertical direction of axis A-Aof between about 0.5 and 6 inches, and most preferably 1 to 3 inches. It is to be appreciated that flotation padshaving smaller or greater diameters and/or thicknesses may also be used, depending upon the specific nature of any contaminates to be collected thereby, and/or the particular characteristics of the water bodyin which the padis to be deployed.

show best each padas including an inner laminar core, an outer coverused to cover the laminar coreas a sleeve, and a tether assemblyused to interconnect the padto one or more adjacent padsin the assembly of the containment boom.